The present invention relates to new 23-oxo (keto) and 23-imino derivatives of the compounds collectively defined as LL-F28249. These LL-F28249 antibiotics preferably are produced by the fermentation of the microorganism Streptomyces cyaneogriseus subspecies noncyanogenus, deposited in the NRRL under deposit accession no. 15773. The morphological characteristics, compounds and method for their production is disclosed in U.S. Pat. application Ser. No. 732,252, filed May 10, 1985, which is a continuation-in-part application of Ser. No. 617,650, filed June 5, 1984 and published in European Patent Application Publication No. 170,006, incorporated herein by reference thereto.
The LL-F28249 components .alpha.-.lambda. are complex macrolides which have a 23-hydroxy substituent, as well as two other hydroxy groups. The selective oxidation of this 23-hydroxy group to a 23-oxo group and the subsequent derivatization of the oxo group to afford 23-imino derivatives are the subject matter of the present invention. These 23-oxo and 23-imino derivatives of the LL-F28249 .alpha.-.lambda. compounds are useful for the prevention, treatment or control of helmintic, ecotparasitic, insect, acarid and nematode infections and infestations in warm-blooded animals and agricultural crops.